The present invention relates to a method of generating conversion formulas for obtaining analysis values and more particularly, to a method wherein such formulas enables the analysis value obtainable by, for example, an analyzer manufactured to be delivered to a customer, to coincide with those obtained by a reference analyzer.
There is a conventional analyzer in which a specimen such as blood and serum is dripped onto a slide to be analyzed that comprises a transparent support provided thereon at least one reagent layer and that exhibits change in optical density once a specimen adheres thereto, thereby reflected density is measured in order to determine presence/absence of a specific component or amount of the component. In such an analyzer, a slide to be analyzed is irradiated with light, and reflected light is collected, thereby based on the reflected light, progress, results or the like of specimen-reagent reaction is determined, and the measurement value is arithmetically processed to determine an analysis value.
However, the degree of reaction on a slide to be analyzed is not linear relative to the optical density of the reflected light. Therefore, if a measurement value is based on an optical reflection density, some conversion formula is indispensable for converting the optical density into the analysis value of concentration of a specific component in a specimen or of enzyme concentration.
With respect to such a conversion formula, it is noted in "Spectrometry in Clinical Biochemical Tests" (by Yoshino and Ohsawa, Gakkai Shuppan Center) that the correlation between a reflectance and concentration of substance can be defined by Kubelka--Munk's formula. This literature further mentions application of Williams--Clapper's formulas and those based on Beer's law. A technique using a conversion formula is disclosed in Japanese Patent Publication Open to Public Inspection (hereinafter referred to as Japanese Patent O.P.I. Publication) No. 32344/1987, while the same applicant proposes introduction of conversion formulas represented by hyperbolas, in Japanese Patent Open to Publication No. 111446/1988.